Use magnet to move 3 colored bubbles, then shoot 3 times to create chain reaction and keep temperature above zero.

Shoot into bubbles before they decay into useless transparent bubbles which decrease temperature.
Red bubbles are full of energy, pink bubbles have less energy but they give one extra bullet. Green bubbles give 3 extra bullets, yellow 6 etc.
Black bubbles.. ..oh, you need to unlock some levels before you reach them.

Collect stars to buy boosters and unlock new levels.

Boosters:
1) 2x - fire two shots instead on one
2) Extra bubbles - more energy bubbles will be spawned
3) Snail - prevent existing energy bubbles from decaying
4) Temperature - boost temperature instantly
5) Bomb - place bomb (while pistol is enabled) to clear portion of arena

And remember, 3 moves, then 3 shoots
HINT Clear all energy bubbles to award extra shoot ;)